A fresh wave of the old horror genre is coming to TV, inviting us to lose ourselves in evocations of our deepest fears. This once cultish corner of the entertainment world is working its way into the mainstream, bringing renewed scrutiny to classic, terrifying icons.

The settings are as varied as Victorian London, contemporary Paris and Anytown, USA. The horrors range from creepy-crawlies in the dark to severed body parts, unearthly creatures to hallucinations and the proverbial bad seed.

Recycled and updated every generation or so, the horror show is deathless.

The digital effects are so advanced, the visuals are primed to scare us out of our seats.

And that’s the point. It’s all about the thrill ride: blood pressure and heart rate go up as eyes open wide to the onscreen horror. A physiological arousal lingers after the show is over, and we want to go back for more. The catharsis never gets old.

Newest TV horrors

Premiering this weekend are “Penny Dreadful,” a melodramatic mashup of horror origin stories on Showtime, and a remake of “Rosemary’s Baby,” based on Ira Levin’s 1967 horror novel, on NBC.

No spoilers here, just the set-up: In the opening moments of “Penny Dreadful,” premiering at 8 p.m. Sunday on Showtime, a woman is awakened by a strange noise. She tiptoes toward it in the dark, extra vulnerable in a skimpy nightgown, one sock off. Before we know we’ve shifted into phantasmagorical territory, she is the victim of some overwhelming supernatural force. All that’s left is the memory of her scream. The story includes appearances by Frankenstein, Dorian Gray, allusions to Jack the Ripper, Dracula and more.

(Why are women drawn, alone in the dark, toward the scary noise? Those of us who dread roller-coasters never get this.)

In the beginning of the slow-incubating “Rosemary’s Baby,” May 11 and 15 on NBC (7 p.m. on Channel 9), we meet the sweet couple who seem to have lucked into the greatest apartment in Paris. Only later do we learn the horrific history of the residence and what’s up with the pregnancy.

“Rosemary’s” is a four-hour tease with a certain French je ne sais quoi, more reminiscent of ABC’s recent “666 Park Avenue” than of the original “Rosemary’s Baby.” “Penny Dreadful” is a psychosexual thriller with literary pretentions, but the first couple of hours don’t inspire patience.

Both succeed at being creepy.

They join a steady march of horror-types into more staid (some say respectable) drama formats: the White Walkers of “Game of Thrones,” and the titular terrors of “The Walking Dead” are only the most obvious reference points for the bleed-over of horror into drama. The post-Rapture horrors of Damon Lindelof’s “The Leftovers” are due on HBO June 29. And the adaptation of Stephen King’s “Under the Dome,” returns for season 2 on CBS June 30.

We could blame the latest rise of horror on the ratings success of “American Horror Story” on FX. The latest installment of that anthology series, “AHS: Coven,” ranked among the top 20 shows on TV in the 18-49 demographic, and among the top 5 in cable. Beyond the remarkable cast, it touched a nerve.

Why it registers

Theories abound as to horror’s claim on us:

“Nothing delights us so much as experiencing danger from a place of safety. We get a tremendous rush of adrenalin — and maybe endorphins — without losing life and limb to do it,” said Denver psychoanalyst Roy Lowenstein by e-mail. “I think the key to good horror is the closeness to, not the distance from, normal human experience. Think of Psycho (AUGGHHHH!) vs. Freddy Kruger (meh).”

“Horror, of all the genres, is the only one that can provoke an involuntary visceral reaction,” said Stephen Graham Jones, author and professor of English at the University of Colorado-Boulder. “Everything else we feel in the arts is elective. We watch a romantic comedy because we want to cry, say, or an action movie so we can participate in heroics. Horror’s different. It can hit you with a moment of revulsion so hard you might want to erase the last five minutes of your life, please. Or, you might leave the theater thinking, that was nothing. But then it’s time to walk through an empty parking garage… The horror, it comes welling back up, whether you want it to or not… Horror always bleeds through.”

“Horror is a compound of terror and revulsion,” CU’s Bruce Kawin explained in his comprehensive 2012 book, “Horror and the Horror Film.” He chronicled how people historically love and may even need horror. “Horror films resonate, politically and personally, with what we know of some extremes of human behavior, and in this they are relevant to an understanding of the world. They grapple with the important mysteries of sex and death, and they may even give us a feeling of temporary power over death.”

If the 1920s-’30s Depression was the “big bad wolf” during the classical age of the horror genre, terrorism is the scary monster today, said CU-Boulder Film Studies director Ernesto R. Acevedo-Munoz. Additionally, he cites “a disproportionate concern with women’s sexuality” that society finds frightening (fear of reproduction being at the core of “Rosemary’s Baby”). The social function of horror is “to assure us everything’s going to be OK,” he said.

Surely, horror is resonant at the moment. Post- 9/11, with robots supplanting humans, drones spying overhead and pollution/climate change threatening the planet, audiences may crave the catharsis of terrifying make-believe.

In a time of great social/technological change, TV executives see the field as ripe. And blurring the lines between drama and comedy and horror opens the genre to a wider audience. Even reality TV is tapping into the horror act: Animal Planet has found ratings success in its “monster week” franchise of scary living things. This month they’ll feature Shannen Doherty in “Blood Lake: Attack of the Killer Lampreys,” the network’s first B-movie from the creators of “Sharknado.”

TV is mining the field once left to cinema and finding satanists, cannibals, synthetic humans, vampires, covens and, now, lampreys in the shower — all the better to scare us with.

“Nothing comes without a price,” the couple is told in “Rosemary’s Baby.”

“Judas,” a new novel by Amos Oz, is a paradox of stillness and provocation. The Israeli author, a long-rumored contender for the Nobel Prize, has reduced the physical action of this story to a tableau of domestic grief.